It is a rather long and weary game, I've been playing for a couple of days and am on Day 29 with all quests but Silver Starter and Liliana's Saviour...sounds like it's going to take a while.
Did you use the same browser? Other browsers use other save locations, so they wont find files from other browsers.
Maybe you (accidently) or your computer delete save files? Computers could do this automaticly if they set so, so maybe check your settings and, if needed, change them.
... as i still mentioned be need to return to hid old browser, only if he changed the browser. As i mentioned above different browsers use different save locations, so if he is still on his "old" browser the change to another browser wont help... only if the game has a online-save it might help, but Jascksmith have a local save...
Why high scores don't working correctly?
For example, if you look to the high scores and kind level is only one person.
And he had score in level 11106.
Quests don't seem to be working right now for this game. I completed quests 1, 2, 3, 4, 5, and 7, and have the in game badges for those as well, but have not earned a single quest yet. It's been a few days too, so I don' think it's delayed.